chore(deps): update dependency monolog/monolog to v2 (GoogleCloudPlatform#1068)

Author: renovate-bot

appengine/php72/laravel-framework/composer.json

@@ -1,6 +1,6 @@
 {
     "require-dev": {
-        "monolog\/monolog": "^1.19",
+        "monolog\/monolog": "^2.0",
         "google/cloud-logging": "^1.14"
     }
 }

appengine/php72/symfony-framework/composer.json

@@ -3,7 +3,7 @@
         "php": "^7.1.3"
     },
     "require-dev": {
-        "monolog/monolog": "^1.19",
+        "monolog/monolog": "^2.0",
         "nikic/php-parser": "^4.0",
         "google/cloud-logging": "^1.14"
     }

logging/composer.json

@@ -2,7 +2,7 @@
     "require": {
         "google/cloud-logging": "^1.20.0",
         "symfony/console": "^3.0",
-        "monolog/monolog": "^1.23"
+        "monolog/monolog": "^2.0"
     },
     "autoload": {
         "files": [